Not that I was under any illusions that Death Valley, Calif., is a temperate place to live, but this is nuts: The overnight LOW on July 11-12 was 107 degrees F . That ties for highest-recorded daily minimum. (The previous 107-degree night was last year, in Oman.) The high in Death Valley on the 11th was 128 degrees F, the 10th highest temperature ever recorded. But steadily warming minimum temperatures may be even more of a concern than record highs. It’s hot nights that kill people, not hot days. And rice, a staple crop for much of the world, needs cool nighttime temperatures to grow — meaning that warming nights are an even greater threat to food security than warming in general. Also, it makes life really really hard for Batman.